The invention concerns a timepiece having a mechanism for the detection and correction of a hands setting, especially in a radio-controlled timepiece.
A mechanism for the detection and correction of a hands setting in a timepiece includes a sender and a receiver for sending and receiving, respectively, a radiation beam. Apertured disks are joined for rotation with the wheels of a hands setting mechanism. One of the disks has a front mirror located approximate the beam sender for reflecting a beam to the receiver. The front mirror has an interruption for passing the beam toward a rear mirror which is disposed remote from the sender, such that a beam reflects therefrom only after passing through apertures in the disks.
An apparatus of this type is known from German Patent No. 38 28 810. It comprises a reflex light barrier with a rotating diaphragm or disk system in front of a mirror pattern extending over different arc lengths. The light barrier generates a beam of radiation. The diaphragm or disk system comprises on the side of incoming radiation an interrupted mirror coating on the seconds wheel of a hands mechanism, which cooperates with it intermediate wheel in the form of an apertured diaphragm in the beam path. To obtain unambiguous angular position detection results, a diaphragm disk combination is located in front of the minute wheel mirror coating, which disk combination comprises the seconds wheel and its intermediate wheel. However, the light barrier evaluation of the different shadowing and passage positions of the diaphragm apertures in the beam path is relatively expensive and requires a relatively long period of time for the pivoting all of the hands drivingly or fixedly connected with the wheels into a predefined reference position, from which they may be advanced into the angular position for the prevailing hands time display in front of the scale face of a radio controlled timepiece of the type described in more detail in U.S. Pat. No. 4,645,357. While the provision of a light barrier in the wheels area of the gear works makes it possible to eliminate a visually disturbing direct optronic query of the angular position of the hands in the face of the timepiece, the apertured diaphragm system is far from optimal with respect to the configuration of the works and the expense of the motor controls.